Synthesis of Silver Nanoprisms with Variable Size and Investigation of Their Optical Properties: A First-Year Undergraduate Experiment Exploring Plasmonic Nanoparticles

Abstract

A robust and reasonably simple experiment is described that introduces students to the visualization of nanoscale properties and is intended for a first-year laboratory. Silver nanoprisms (NPs) that display different colors due to variation of their plasmonic absorption with respect to size are prepared. Control over the size of the silver nanoprisms is achieved using a novel approach, where bromide is added to the reaction as a size-determining agent, and silver ions are reduced by borohydride in the presence of citrate and peroxide as stabilizing and shape-directing agents, respectively. In a typical experiment, four dispersions of silver nanoprisms with different sizes are produced that are colored from blue (largest) to yellow (smallest). The colors attainable in between are violet, purple, red, and orange. The synthesis of these colored silver NPs is described for the first time as an undergraduate experiment. Once synthesized, the nanoprisms are characterized using UV−vis spectroscopy, and a Beer’s law experiment can be performed. Furthermore, concepts of redox chemistry and visible spectroscopy can be reinforced in this experiment, and it can be further adapted for upper-level laboratories focused on the investigation of nanoparticle properties by more advanced techniques.

Facile Preparation of Pyrene-templated Hexagonal-shaped Gold Nanoplates

“…Especially, anisotropic gold nanostructures are an interesting class of structures due to their unique optical, electrical, magnetic and catalytic properties that directly correlate with their shape and size [3][4][5][6]. They have been synthesized using a variety of methods, including chemical reduction and seed-mediated growth methods in aqueous phase [7].…”

Toxicity study of new metal nanoparticles functionalized with fluorescein derivatives as novel image systems

“…Additionally, there is also need for more information on NPs toxicity. Recently has been demonstrated that physiological barriers such as pulmonary and gastro-intestinal tract are affected [1,2].The main objective of this work is to use functionalized metal NPs, as emissive agent markers, assess their internalization in cells and evaluate toxicity to cells.Using the emissive two probes synthesized in a one-pot reaction using fluoresceine as chromophore, several gold (Au), round shape, and silver (Ag) NPs (round and triangular shapes) were functionalized in organic media and water by Brust [3] and Turkevish [4] methodology, using tetraoctylammonium bromide (TOABr) as a common stabilizer and sodium borohydride as reducing agent. All has been characterized by UV-vis and emission spectroscopy, transmission electron microscopy (TEM) (Figure 1), and Light scattering.…”

“…Additionally, there is also need for more information on NPs toxicity. Recently has been demonstrated that physiological barriers such as pulmonary and gastro-intestinal tract are affected [1,2].…”

Preparação de nanopartículas de prata e ouro: um método simples para a introdução da nanociência em laboratório de ensino

“…A nanociência e o resultado dela, a nanotecnologia, já são temas muito explorados e discutidos em vários cursos de graduação em outros países. [8][9][10] As aulas experimentais de Química Inorgânica ou Físico-Química são, portanto, um caminho bastante adequado para a introdução dos conceitos de nanociência para alunos de graduação do último ano de curso. Isso se deve, não apenas pelo interesse tecnológico em torno do assunto, mas também pelo fato de que um experimento simples como esse que será apresentado aqui resgata e coloca em prática conceitos básicos de Química, como teorias de ligação metálica, estrutura atômica, reações de oxidação-redução e espectroscopia, ao mesmo tempo em que introduz novos conceitos, muitos deles não vistos em sala de aula, como o efeito de confinamento quântico e a ressonância de plasmons de superfície.…”